Preheat the oven to 300°F. Line 3 loaf pans with parchment paper, or butter and flour them.
Carefully pour the boiling hot water over the grated carrots and raisins in a large bowl, then set aside to cool for a few minutes while you measure the remaining ingredients. Measure the dry ingredients into a large bowl and whisk together to incorporate, or use a sifter.
Add the honey and oil to the cooled carrot mixture, and stir gently to avoid splashing. Fold the carrot mixture into the flour mixture using a rubber spatula. Mix together just until all the flour is moistened.
Pour batter into prepared pans. Bake for 45 – 50 minutes. A knife inserted in the center of the cake should come out clean. Allow the cake to cool completely before serving.